1. Field of the Invention
The present invention relates to a working machine in which an upper frame of an upper rotating body has a piping structure.
2. Description of the Related Art
In an upper frame of a hydraulic excavator, a pipeline connecting front and back hydraulic devices may be disposed in a front-back direction through left and right side decks.
For example, when a hydraulic pump is disposed at a back portion of the frame and a main control valve for operating a hydraulic actuator is disposed at the side deck, an oil supply/discharge pipeline connecting the pump and the valve is disposed so as to pass below the side deck.
Japanese Unexamined Patent Application Publication No. 11-200407 discloses a structure for installing a pipeline at an inner surface of a decorative cover which is disposed at an outer side of a side deck.
In the former method of passing the pipeline below the side deck, since the pipeline is directly pushed by an upward force from below by, for example, soil and stones, it tends to be damaged or to break. In addition, since steps are actually formed at a plurality of locations in front and back portions of the side deck, the pipeline must be passed through holes that are formed in the steps. Therefore, the strength of the deck is reduced by the holes.
The pipeline may be passed below the steps and covered with a protective cover. However, since the protective cover, itself, may be damaged by an upward pushing force from below it, the reliability with which the pipeline is protected is low. Therefore, costs are increased.
In the latter technology, since the pipeline is covered with a decorative cover which has a greater tendency to come into contact with obstacles than the protective cover and which has low strength/rigidity, the pipeline is not sufficiently protected. In addition, since the pipeline must be secured to the inner surface of the decorative cover, the pipework becomes troublesome.